Analog circuit code golfing:
Long ago, a current mirror to charge a 12v battery bank from a "12v" iPod charger, evading the usual regulator voltage drop.
More recently, a circuit to trip a solenoid when a bit of hot dog goes missing from two leads.
I needed two op amps for sensitivity, because over a day or so the hot dog dries up to nearly an open circuit. Still, only a handful of parts, on the smallest breadboard made.
Yes, I'm a walking cliche, a better rat trap. My only excuse is this was during the pandemic. I excelled at an electronics segment of shop class back in 1968 junior high school, and I never asked my parents for a kit to go on from there.